In the automobile industry, there has been extensive research conducted into improving emissions. In particular, in some countries, regulations are in force to reduce the total amount of vaporized fuel gas to 0.5 g/day or less in order to minimize emission of hydrocarbon (HC) included in the vaporized gas of gasoline fuel, and the total amount of vaporized fuel gas will be limited to 0.054 g/day or less.
In general, to meet the regulations, recently, the automobile industry minimizes the occurrence of the vaporized fuel gas, which penetrates a fuel tank, by improving a material of the fuel tank and optimizing connection structures, and on the other hand, the automobile industry adopts a vaporized fuel gas recirculation system in which a canister is applied to a fuel supply device.
Here, the canister contains an absorbent material which may absorb the vaporized fuel gas from the fuel tank that stores volatile fuel, and the canister is connected with the fuel tank and collects the vaporized fuel gas in order to prevent the vaporized fuel gas, which is evaporated from a float chamber of a vaporizer and the fuel tank, from being discharged into the atmosphere.
The vaporized fuel gas, which is collected in the canister as described above, is introduced back into an engine by a purge control solenoid valve (PCSV) controlled by an engine control unit (hereinafter, referred to as an ‘ECU’), and then the vaporized fuel gas is combusted, such that the vaporized fuel gas is recirculated.
In a case in which an apparatus for purging the fuel vapor in the related art is used together with an exhaust gas recirculation (EGR) apparatus and a turbocharger, it is difficult to accurately control an EGR ratio, and it is difficult to purge the fuel vapor when intake boosting is carried out by the turbocharger.
Therefore, there is a need for research on an apparatus for purging fuel vapor which is capable of accurately controlling the EGR ratio and purging the fuel vapor even though the intake boosting is carried out by the turbocharger.
The above information disclosed in this Background section is only for enhancement of understanding the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.